公开(公告)号：CA1293814C

公开(公告)日：1991-12-31

申请号：CA580379

申请日：1988-10-17

Applicant: IBM

Inventor： LIANG BOB C C

IPC: G06F17/50 ,  G06T15/00 ,  G06T17/20 ,  G06F15/72

Abstract: A Pipeline and Parallel Processing system for generating Surface Patches for both Wireframe and Solid/Shaded Models in a Raster Graphics Display. The inputs to a Transformation Processor are the parameters for the Rational Bezier Surfaces: a 2-dimensional array of control points, and weights. The outputs are the coordinates of the corner points and the normals (to the surface) of the patches, which make up the surface. The system consists of three Pipeline stages: 1. A front-end processor fetches the data from memory and feeds the Transformation Processor: 2. four Floating Point Processors in Parallel for tessellating the surfaces into small patches; and 3. one Floating Point Processor for generating normals at the vertices of the small patches. The output is sent to the rest of the Graphics System for clipping, mapping, and shading.

公开(公告)号：CA2011507A1

公开(公告)日：1990-10-28

申请号：CA2011507

申请日：1990-03-05

Applicant: IBM

Inventor： GONZALEZ-LOPEZ JORGE ,  LIANG BOB C C ,  TANNENBAUM DAVID C

IPC: G06T1/00 ,  G06F17/17 ,  G06T1/20 ,  G06T3/00 ,  H04N7/36 ,  G09G5/00

Abstract: A system and method for processing image data in a graphics display system using parallel processing. A source image represented as an array of image pixel values is convolved by a kernel function to enhance selected features and assist in image analysis. Bi-linear interpolation is implemented to preserve picture quality when a source image is enlarged or reduced. A series of processing elements connected in parallel are used to speed image transformation and interpolation. The application of convolution is divided between the processors so that the processing with adjacent pixels overlaps and output image pixels are generated in fewer machine cycles. A pipeline architecture continually processes values from the parallel processors through validation and conversion to generate the final image.

公开(公告)号：CA1264878A

公开(公告)日：1990-01-23

申请号：CA523774

申请日：1986-11-25

Applicant: IBM

Inventor： HASKELL KIRK S ,  LIANG BOB C C

IPC: G06T11/20 ,  G06T15/30 ,  G06F15/72

Abstract: A method for drawing a curved figure on a display device under transformation, clipping, or mapping, is described which includes testing to determine whether transformation is to be performed; transforming parametric equations for the figure to be transformed and drawn; testing to determine whether the figure to be drawn is to be clipped against predetermined clipping boundaries; computing an extent of the figure to be drawn; applying a box clip test for trivial clipping for the entire figure; rejecting those figures which are entirely outside the viewport as determined by the trivial clipping test; accepting the entire figure to be drawn which has been determined to be completely within the clipping box; mapping the parametric equations if mapping is required; generating line segments for the figure to be drawn.

公开(公告)号：CA1241467A

公开(公告)日：1988-08-30

申请号：CA502057

申请日：1986-02-18

Applicant: IBM

Inventor： LIANG BOB C C ,  TSAKIRIS TODD N

IPC: G06T11/40 ,  G09G3/00

Abstract: Method and apparatus for filling convex polygons for display in a raster graphics system is described. Starting from the bottom of the polygon, horizontal lines are drawn to fill the polygon as y-value increments . A polygon-fill processor includes two modified Bresenham line generators.

公开(公告)号：CA1311317C

公开(公告)日：1992-12-08

申请号：CA561202

申请日：1988-03-11

Applicant: IBM

Inventor： CALLAHAN ROBERT M ,  HEMPEL BRUCE C ,  LIANG BOB C C

IPC: G06F15/62

Abstract: A method is described for clipping two and three dimensional graphic primitives for use in a computer graphics workstation. During the first clipping stage, the system removes all graphic primitives which lie outside an arbitrary clipping volume or window that is an enlargement of the desired viewing volume or window. This clipping volume (window) is then projected and mapped onto a virtual viewport which is larger than the real viewport. After this mapping occurs, rendering effects (such as line styles, line width, pattern fill, hatch fill, etc.) are applied to the primitive. A subsequent stage of clipping is then applied to clip the virtual viewport to the real viewport which is the user's visible area. Use of the clipping volume (window) during the first stage of clipping makes it simpler to transform geometric primitives which are partially visible to the viewer, and gives visible primitives a richer set of invariant geometric properties so that their rendering effects may be more easily and correctly carried out. KI986-023

公开(公告)号：CA1309200C

公开(公告)日：1992-10-20

申请号：CA573782

申请日：1988-08-04

Applicant: IBM

Inventor： GONZALEZ-LOPEZ JORGE ,  LIANG BOB C C

IPC: G06T15/40 ,  G09B9/30 ,  G06F15/72

Abstract: HIDDEN LINE REMOVAL METHOD WITH MODIFIED DEPTH BUFFER Polygon vertex data is processed in three steps to create a graphics display without hidden lines and without gaps in the displayed lines. The technique permits the processing of triangles rather than polygons having four or more sides. In the first step, the Z values for the display points for the visible edges of the polygons are identified and assigned a reserved value ZCLOSE in a frame buffer. In the second step, the polygons are tessellated into triangles and the Z values for the display points on the triangles are computed and each depth buffer storage location is updated so as to contain the value of points closest to the viewpoint while the frame buffer is written with a background color. In the final step, the Z values for the display points of the polygon edges are again computed and compared-with the corresponding Z values in the depth buffer. The depth buffer is updated with the computed values if the stored value is equal to ZCLOSE or if the computed value represents a position closer to the viewpoint than the stored value and the frame buffer is then written with a foreground color for the display point in question.

公开(公告)号：CA1304824C

公开(公告)日：1992-07-07

申请号：CA581529

申请日：1988-10-27

Applicant: IBM

Inventor： GONZALEZ-LOPEZ JORGE ,  HEMPEL BRUCE C ,  LIANG BOB C C

IPC: G06F17/50 ,  G06T15/50 ,  G06F15/72

Abstract: A lighting model processing system for a computer graphics workstation's shading function includes multiple floating point processing stages arranged and operated in pipeline. Each stage is constructed from one or more identical floating point processors. The lighting model processing system supports one or more light sources illuminating an object to be displayed, with parallel or perspective projection. Dynamic partitioning can be used to balance the computational workload among various of the processors in order to avoid a bottleneck in the pipeline. The high throughout of the pipeline system makes possible the rapid calculation and display of high quality shaded images.

公开(公告)号：CA1264879A

公开(公告)日：1990-01-23

申请号：CA523775

申请日：1986-11-25

Applicant: IBM

Inventor： HEMPEL BRUCE C ,  LIANG BOB C C

IPC: G06F3/153 ,  G06T11/00 ,  G06T15/30 ,  G06F15/68 ,  G06F15/72

Abstract: A display processor in a raster graphics display system includes a transformation, clipping and mapping feature which controls the transformation, clipping and mapping of graphics data. A control byte contains 5 bits identified as: M- Window to viewport mapping; P-perspective projection; D-2D/3D mode; T-transformation; and C-clipping. Each bit in the control byte is tested to determine what operations are to be performed on the figure to be drawn. For example, if the D bit is one, indicating a three dimensional figure and the T bit is one, indicating transformation, and the C bit is one, indicating clipping, the P bit determines whether the clipping will be perspective or non-perspective clipping and the M bit determines whether the figure to be drawn is to be mapped to the view port.